oracle performance tuning basics

Oracle|sql language []oracle pl/sql Language Foundation Oracle Pl/sql Language Basics Pl/sql is Oracle's extension of the standard database language, Oracle has integrated PL/SQL into Oracle servers and other tools, and more dev

The Oracle tutorial you are looking at is: Oracle SQL Performance Tuning Series learning three. 8. Use the Decode function to reduce processing time Use the Decode function to avoid repeatedly scanning the same record or repeating the same table. For example: SELECT COUNT (*), SUM (SAL) from EMP WHERE dept_no = 0020

oracle| Performance | optimization 46. Connect multiple Scans If you compare a column to a limited set of values, the optimizer may perform multiple scans and concatenate the results. Example: SELECT * From lodging WHERE MANAGER in (' Bill GATES ', ' KEN MULLER '); The optimizer may convert it to the following form SELECT * From lodging WHERE MANAGER = ' BILL GATES ' or MANAGER = ' KEN MULLER ';

First, the overall introduction:Oracle databases and databases represent the foundation of all Oracle database objects. Oracle is a large relational database based on advanced Structured Query Language (SQL), in other words, manipulating a large collection of regular data in a convenient, logically managed language. is one of the most popular database of C/s architecture.Second, the experience of the first

make paged queries:In this I learned that RowNum used to do top-n analysis. is to obtain the first few data, first query out with a column with order by order as a virtual table with RowNum Select the first few we want and then we can use an ORDER BY statement to select the order output we want, note what to sort must be in the above select Found in the virtual table. sequence Create sequence sequence name: Used to generate an incremented value, but does not guarantee continuousDelete a drop se